Carbanion center
A carbanion is an anion containing an even number of electrons with a free electron pair on a tetravalent carbon atom. Carbanions include both anions with a negative charge localized on a carbon atom and anions with a delocalized negative charge whose charge is localized on a carbon atom in at least one of the canonical structures [1] :
Content
Properties
Carbanions are conjugate bases for hydrocarbons acting as Lewis acids.
Carbanionic centers can be in the state of sp 3 hybridization (for example, Cl 3 C - ), intermediate between sp 3 and sp 2 hybridization (for example, in enolate anions ) and sp 1 hybridization (in R-Cβ‘C acetylides - ).
Ways of getting
- Solvent ionization for metal-organic compounds.
- The effect of strong bases on a fairly acidic (polarized) bond CH.
- Attaching anions by multiple bonds.
Stabilization factors
- The spatial factor is the screening of the reaction center.
- Resonant factor - the more resonant structures a carbanion has, the more stable it is.
- The nature and position of substituents in the carbon chain - acceptor substituents stabilize carbanion.
Chemical Properties
- Interaction with electrophiles.
- Oxidation to radicals .
Notes
Literature
- Knunyants I.L. and others. Vol.2 Duffa-Medi // Chemical Encyclopedia. - M .: Soviet Encyclopedia, 1990. - 671 p. - 100 000 copies - ISBN 5-85270-035-5 .